This invention relates to an improved process for imparting an improved corrosion-resistant property to particles having metal surfaces. In particular, the invention relates to a means to achieve an improved combination of good chemical resistance and good electroconductivity on metallic particles. The invention also relates to the novel products formed by the aforesaid process and to novel conductive paint compositions utilizing said products.
It has long been a problem to provide electrically-conductive particles which have good corrosion resistance. One approach to such particles is described in U.S. Pat. Nos. 4,092,459 and 4,137,361 to Robert J. Deffeyes. Deffeyes discovered that carbiding the surface of, say, a nickel powder provided a nickel powder of good conductivity and good chemical resistance.
Takahasi in U.S. Pat. No. 3,904,448 have described a thin coating of nitride on a metallic powder product. The coating offered good corrosion resistance but had relatively poor electroconductive properties. The present inventor has discovered a way to further improve the particle-treating processes of the general type described by such inventors. Such particles find exceptional value in the formation of coating compositions for electroconductive, or electromagnetic-shielding applications.